Wireless personal area networks based on OFDM and UWB technologies like the MBOA standard may directly interfere with narrowband devices which are close to such wideband devices. At present, no specific interference mitigation techniques are implemented in the UWB standard based on OFDM (MBOA).
Orthogonal frequency-Division Multiplexing (OFDM) is a method of digital modulation in which a signal is split into several narrowband channels (sub-carriers) at different frequencies. In order to avoid in-band spectral interference, WO 2005/006698 (INTEL) proposes to puncture, i.e. remove, selected sub-carriers. More precisely, this puncturing is made, taking into account channel knowledge, after the OFDM modulation in the transmitter, whereas a depuncturing is performed in the receiver before the OFDM demodulator. Because of the puncturing of some sub-carriers, the size of the encoded block of data which may be converted into OFDM symbols has to be reduced. Consequently, not only the software of the MAC (“Medium Access Control”) entity of the UWB device may be modified to take into account this size reduction of the data block, but the receiver needs to know the actual used puncturing scheme, for example through the transfer of control information from the transmitting device to receiving device, leading to an interruption of the transmission of the useful data between the transmitting device and the receiving device.